Grinding wheel



May 10, 1966 R. T. CASERTA GRINDING WHEEL Filed Sept. 26, 1963 INVENTOR RICHARD 7.' CASERTA ATTORNEYS.

' involved in changing to a new grinding wheel.

United States Patent 3,250,045 GRINDING WHEEL Richard T. Caserta, 721 Abbey Lane,, Lansdale, Pa. Filed Sept. 26, 1963, Ser. No. 311,737 Claims. (Cl. 51209) This invention relates to an improved grinding wheel of the resinoid type and more particularly to a grinding wheel which may be more easily and reliably usedthan those presently in existence.

In using grinding wheels as presently provided it is necessary to secure the grinding wheel to a shaft which will drive or rotate the grinding wheel about its center in a generally fiat plane. In order to secure the grinding wheel to the driving shaft an adapter has heretofore been utilized. Such an adapter basically comprises at least two members, at least one of which can be threadingly secured on the driving shaft with the grinding wheel being sandwiched between the two members. Means were provided in order to tighten or draw the two members closely toward each other and thereby tightly hold the grinding wheel.

Also, since this type of grinding wheel is used in a nearly fiat position with the grinding done by the lower peripheral edge, a recess has been provided in the wheel so that the retainingnut would not hit the work. This recess considerably weakens the wheel.

Beside the strength considerations there are many practical shortcomings to the-foregoing assembly.

First, the operation of removing one of the two holding'members in order to separate the grinding wheel from the driving shaft with the subsequent replacement of a new grinding wheel and the return of the holding member to the driving shaft is a time-consuming operation. Furthermore, different grinding wheels may require different kinds of adapters and this adds to the time This further creates a danger wherein an operator in his haste or carelessness may not change the adapter and thus the net result will be the use of an improperadapter which will result in the eventual loosening of the grinding wheel with possible damage to both the driving shaft, the grinding wheel and even to personnel in the area.

In view of the foregoing, it has been suggested to provide adapters which can be discarded whenever it is necessary to change a grinding wheel. However, this is not only expensive but the adapters themselves did not possess the necessary strength and reliability. Another suggestion involved the adhesive attachment of an adapter to the central face of the grinding wheel. However, this has proved to be unsatisfactory as the adapter was eventually separated from the grinding wheel at an indeterminate time thereby creating possibility of harm to personnel in the area of the driving shaft and also damage to the driving shaft and to the grinding wheel itself.

Yet another shortcoming of grinding wheels heretofore used, as was previously mentioned, is the necessity of providing a recess to accept a retaining nut. This recess considerably weakens the grinding wheels. Such weakening is caused by the high stresses developed during rotation of the grinding wheel since the centrifugal force of rotation has a tendency to straighten out or eliminate the recess.

It is therefore an object of the present invention to provide an improved grinding wheel which completely eliminates the use of unsatisfactory adapters.

Yet another object of the present invention is to provide an improved grinding wheel which can be simply and quickly attached to a driving shaft and which can be simply and quickly removed from a driving shaft.

Still another object of the present invention is to pro- 3,250,045 Patented May 10, 1966 vide an improved grinding wheel which presents very little risk of danger to personnel in the area or to the drive shaft or grinding wheel.

Another object of the present invention is to provide an improved grinding wheel of a simpler shape which eliminates a central recess and thereby achieves a stronger grinding wheel.

The foregoing as well as the other objects of this invention are achieved by providing an improved grinding wheel which basically comprises alternating plies of resinabrasive material and plies of reinforcing material. An internally threaded member with a base plate firmly embedded within the grinding wheel and preferably between two of the reinforcing plies enables the grinding wheel of the present invention to be easily inserted upon or removed from the threaded end of a driving shaft.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view taken generally from the rear face of an improved grinding wheel of the present invention;

FIG. 2 is an exploded view of the grinding wheel in FIG 1;

FIG. 3 is an enlarged sectional view taken along the lines 33 of FIG. 1 with the driving shaft having been eliminated; and

FIG. 4 is an enlarged elevational view of the internally threaded member of the improved. grinding wheel of the present invention.

Referring now in more detail to the various figures of the drawing wherein like reference characters refer to like parts there is shown at 10 in FIG. 1 an improved grinding wheel of the present invention. As shown in FIG. 2, the grinding wheel 10 basically comprises a first resinabrasive ply 12, a first reinforcing ply 14, a second resinabrasive ply 16, a second reinforcing ply 18 and an inner resin-abrasive ply 20. As further shown in FIG. 2 the improved grinding wheel of the present invention also includes an internally threaded member or nut 22 which enables the improved grinding wheel of the present invention to be simply and reliably secured to a driving shaft such as shaft 24 in FIGS. 1 and 3.

An advantageous size wheel is generally about inch in thickness (outside of the hub area) and approximately six to nine inches in diameter.

The internally threaded member 22 basically comprises a nut 26 and a plate 28 as illustrated in FIG. 4, with the nut extending outwardly of the grinding wheel for a substantial distance at least as great as the internal penetration of the nut in the grinding wheel. The nut is of such a size that standard commercial open end wrenches will properly engage the flat surfaces thereof. The nut 26 has an internally threaded bore 30 which is adapted to receive the threaded end 32 of the driving shaft 24. The nut 26 also includes a depending skirt 34 which is actually an integral part of the nut 26 and which may also be internally threaded. As illustrated in FIG. 3 the skirt 34 depends through a complementary opening in the plate 28 with the nut 26 being welded, brazed or otherwise securely fastened at 36 to the plate 28 in order to firmly secure the two members together.

The materials from which the components of the present invention are made are well known and are presently used in conventional grinding wheels. For instance the resin plies 12, 16 and 20 are basically a combination of a single or mixture of heat hardening or thermo-setting resins such as phenol formaldehyde with appropriate abrasive agents. The reinforcing plies 14 and 18 may be of glass cloth or other strong reinforcing material. The internally threaded member 22 is preferably of a metallic material although other materials are contemplated.

A typical resin-abrasive composition utilized in connection with the present invention is in parts by volume (a) aluminum oxide abrasive (83.3%), (b) phenolic resin (9.4%), (c) kryolite (6.5%) and (d) lime (0.8%) The foregoing ingredients are pressed to 'a finished wheel density of approximately 2.66 grams per cc.

In the manufacturing process of making the grinding wheel a suitable round mold is employed and a layer of resin and abrasive material comparable to ply 12 is placed in the mold. A reinforcing ply 14 is then placed upon the layer 12 and the second layer of resin and abrasive material 16 is formed on the ply 14. In this connection it is to be noted that the reinforcing plies 14 and 18 have preformed central openings 38 in order to receive the projecting member 22. It should be noted that the central openings in each of the plies of reinforcing material are so designed that in the finished wheel plate 28 will extend radially beyond the openings in the reinforcing plies sufficiently that the reinforcing plies will secure the plate.

The-internally threaded member 22 is then placed upon the layer 16 so that depending skirt 34 projects through the opening 38 in the next reinforcing ply 18 which is placed on layer 16. When this is done skirt 34 will also pass through the layers 16 and 12 in order that the finished grinding wheel may have a central through opening such as the opening 40 as illustrated in FIG. 3.

In studying FIG. 3 it should be noted that the front or working face of the grinding wheel is almost completely fiat and does not have a recessed area. Furthermore, each of the succeeding resin plies and reinforcing plies are flat.

The manufacturing process is then completed by placing second reinforcing ply 18 so that it lies against the upper surface of the plate 28. The assembly process is completed by the provision of a smaller hub-like layer of resin and abrasive material comparable to ply 20. The disc is then pressed to the desired shape. The assembly is then heated in a curing oven in accordance with wellknown techniques in order to produce an essentially homogeneous bond between the reinforcing and the abrasive particles. The fiat, undistorted plies of reinforcing and abrasive particles are better able to withstand the grinding and centrifugal stresses.

Of course the make-up of the grinding wheel may vary in many ways, such as, by eliminating any or all of the reinforcing plies or by adding additional plies of reinforcing and, or abrasive resin or by changing the shape of the wheel in the area between the extremity of the hub and its periphery by dishing the wheel such that this area assumes a somewhat conical shape.

The term grinding wheel has been used throughout the specification and claims and is intended to include abrasive attachments or discs Whether flexible or rigid.

In studying'the finished grinding wheel in FIG. 3 it is to be noted that it can be simply threaded upon the shaft 24 by rotating the grinding wheel such that internally threaded opening 30 is aligned with the threads 32 of the shaft 24. The grinding wheel 10 is then simply revolved until the threads 30 and 32 are engaged.

In use the shaft 24.is driven in a sense opposite to the advance of the engaged threads 30 and 32 so that the driving of the shaft 24 has a tendency to' tighten rather than loosen the engagement of the grinding wheel 10 and the shaft 24. If desired a stop member (not shown) may be formed on the shaft 24 in order to halt the inward advance of the grinding wheel 10.

It is thus seen that the internally threaded member 22 is essentially formed as an integral element of the grinding wheel 10 and that the member 22 can be separated from the remainder of the grinding wheel only by actual breaking through of several plies of the grinding wheel. The various plies and the member 22 cannot be separated through a gradual wearing-away process as was the case with adhesively secured adapters. Also, the front or working face of the grinding wheel is essentially completely flat.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed as the invention is:

1. In a grinding wheel comprising a disc-like member having a substantially fiat abrasive face and a relatively small through opening at right angles to the abrasive face in the central portion thereof with said grinding wheel also including a resin-abrasive material bonding a plurality of reinforcing plies, an internally threaded member with a thin integral plate with considerable surface area, positioned between two of said reinforcing plies and beneath said abrasive face, said plate extending a considerable distance between said plies, said internally threaded member also comprising an integral nut defining said opening and extending from said plate away from said abrasive face, said nut extending outwardly of said wheel for a substantial distance whereby said grinding wheel may be secured to a threaded shaft for rotation therewith without the need of an adapter flange by engaging the threaded end of said shaftdirectly within said internally threaded member.

2. The invention of claim 1 wherein said reinforcing plies are of glass cloth.

3. The invention of claim 1 wherein said nut includes an embedded depending skirt extending toward said abrasive face.

4. The invention of claim 3 wherein said depending skirt is also internally threaded.

5. The invention of claim 1 wherein said nut extends outwardly for a distance at least as great as its internal penetration in said grinding wheel.

References Cited by the Examiner UNITED STATES PATENTS 93,413 8/1869 Calder 5l206 3,041,797 7/1962 Moffiy 5 1378 3,081,584 3/1963 Bullard 5l-209 ROBERT C. RIORDON, Primary Examiner.

LESTER M. SWINGLE, Examiner. L. s, SELMAN, Assistant Examiner. 

1. IN A GRINDING WHEEL COMPRISING A DISC-LIKE MEMBER HAVING A SUBSTANTIALLY FLAT ABRASIVE FACE AND A RELATIVELY SMALL THROUGH OPENING AT RIGHT ANGLES TO THE ABRASIVE FACE IN THE CENTRAL PORTION THEREOF WITH SAID GRINDING WHEEL ALSO INCLUDING A RESIN-ABRASIVE MATERIAL BONDING A PLURALITY OF REINFORCING PLIES, AN INTERNALLY THREADED MEMBER WITH A THIN INTEGRAL PLATE WITH CONSIDERABLE SURFACE AREA, POSITIONED BETWEEN TWO OF SAID REINFORCING PLIES AND BENEATH SAID ABRASIVE FACE, SAID PLATE EXTENDING A CONSIDERABLE DISTANCE BETWEEN SAID PLIES, SAID INTERNALLY THREADED MEMBER ALSO COMPRISING AN INTEGRAL NUT DEFINING SAID OPENING AND EXTENDING FROM SAID PLATE AWAY FROM SAID ABRASIVE FACE, SAID NUT EXTENDING OUTWARDLY OF SAID WHEEL FOR A SUBSTANTIAL DISTANCE WHEREBY SAID GRINDING WHEEL BE SECURED TO A THREADED SHAFT FOR ROTATION THEREWITH WITHOUT THE NEED OF AN ADAPTER FLANGE BY ENGAGING THE THREADED END OF SAID SHAFT DIRECTLY WITHIN SAID INTERNALLY THREADED MEMBER. 